Power unit



April 21, 1931. H. SOPKIN ET AL POWER UNIT Filed Feb. 5, 1929 2 Sheets-Sheet 1 i i l 62 unnuDn: mun: ummn pun. um": fl Hun.

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April 21, 1931. I H SQPKIN ET AL 1,801,939

" POWER UNIT Filed Feb. 5, 1929 2 SheetsSheet 2 Patented Apr. 21, 193.1

HARRY s orxmnnn BENJAMIN H. GQRMAN, or ornoaeo, ILLrnoIs POWER UNIT Application filed February 5, 1929. Serial No. 337,637.

This invention relates to a power unit and has special reference to a power unit for operating machines of a type such as sewing machines which are intermittently controlled.

More particularly this invention has reference to a power unit for operating sewing machines and the like which unit comprises essentially a continuously operating driving mechanism and a driven mechanism having a frictional engagement therebetween where-by 7 when an operating pressureis applied, power is transmitted to the mainshaft of the machine and when the operating pressure is removed, either manually or mechanically, the main shaft is disconnected and a brake is automatically applied thereto to stop the rotation of the main shaft immediately.

In the embodiment illustrated 1n the draw I ings, the driving means ispivotally mounted on a supporting table and is actuated into an operative relation with the driven mechanism by means of a tiltable foot treadle. When the operating pressure is removed from the treadle, the weight of gravity carries the driving means automatically into an inoperative relation with the driven mechanism.

One of the objects of this invention is to provide a power unit of the, type described above, which is simple in construction, comparatively inexpensive to manufacture and durable. V 7

Another object of this invention is to pro.- vide a power unitias described above wherein the operating mechanism consumes but a minimum amount of manual operating pressure.

A further object of thisinvention is to provide a power unit as hereinbefore mentioned in which the operating mechanism, 40 apart fromthe control mechanism, is arranged compactly for cleanliness in operating upon material, and in avoiding the collection of dirt and dust therein, and is arranged efficiently for eliminating auxiliary shafts and other operating mechanism re quiring attention for their care upon an operator. V

Other objects and advantages will be pointed out hereinafter and for a more complete description of the nature, scope and characteristics of this invention reference may be had to the following description and accompanying drawings, in which latter i Figure 1 is a front elevational view, partially insection, of the sewing machine operated by a power unit, which latter embodies the invention of this application.

Fig. 2 is a vertical sectional view taken on the line 22 of Figure 1. v

Fig. 3 is a front elevational View partially 1m in section of a second embodiment of this in- 'vention; and

Fig. 4 is avertical sectional view taken on the line l-4: of Fig. 3. 7

Referring now to the drawings, and-more particularly to Figures 1 and 2 thereof, a

sewing machine 10 of any usual type is shown mounted on an operating table 11. It is to be understood that various kinds of power machines may be operated by thefdevice of this invention, and the particular means shown is but one of a number of machines which are manually andintermittently controlled. By this latter it is meant that the starting of the machineis controlled manually at the will of the operator.. However, no definite cycle or period of time elapses betweenthe various operations of the machine in the embodimfents shown in the drawings although it is to be understood that a mechanical trip may be employed to accomplish this result if desired. a The main shaft 12 of the sewing machine is connected by means of a link chain or belt 13, which latter is connected between a gear or pulley of the main drive shaft 12, and a gear or pulley 14 on an auxiliary shaft 15. The shaft 15 is in turn journaled in bearings 16 and 17, the bearing 16 being supportedv by a bracket 18 mounted on the underneath side of the operating table 11, and the bearing 17 being formed integrally with a bracket 19 like Wise secured to the underneath side of the operating table 11. A pinion 20 is fiwdly mounted on the auxiliary shaft- 15 adjacent the pulley 14, whereby a rotation of the shaft 15 by means of pinion 20 rotates the pulley 14 to drive in turn the main shaft 12 of the sewing machine.

A transmitter shaft 21 is join-nailed on the lower ends of the brackets 18 and 19 and carries in a fixed relation therewith a gear and a grooved wheel 23. In order to facilitate the assembling of the grooved wheel and gear 22 on the shaft 21, the wheel and gear may be formed integrally. However, should it be desirable for these elements to be made of different materials, they may be readily secured together or may be fixed separately to the shaft 21.

Cooperating with the grooved wheel 23 is a wedged wheel 24 mounted on the mot-or shaft 25 of an electric motor 26. The complementary wheels 23 and 24 form a friction gear of the wedge-faced type. This particular construction gives a maximum resistance to slipping with a given radial pressure. This is an important factor entering into the construction of the power unit, since the operating pressure is manually applied, as will here inafter be more fully pointed out.

When the radial force is applied to the grooved surface, or when the wedged wheel engages the grooved wheel, a rotation of the motor shaft 25 will operate to rotate the wedged wheel 23 to impart motion to the ma 1n shaft 12, as hereinbefore described. In order that there be a smooth continuous rotation of the motor shaft 25 and a subsequent smooth starting operation of the main shaft 12 of the sewing machine, a weighted member 27 similar in effect to a fly wheel is fixedly mounted. on the motor shaft 25 adjacent the wedged wheel 24. This latter construction for the sake of brevity may be termed a balanced motor shaft. It may be desirable to have the wedged wheel made of a fibrous or other like materials in order to increase the resistance to slipping, whereafter the weighted member 27 may provide a securing means for attaching the fibrous material of the wedged wheel thereto. In the latter instance a plate 28 havinga peripheral securing lip 28a is secured on the outer side of the wedged wheel 24-, and has securing means such as screws extending therethrough and through the wedged wheel, the latter likewise having a peripheral lip 'to be fastened into the weighted member 2?. However, it may readily be seen that the Weighted member 27 and the wedged wheel 24 may be formed integrally of a single casting if desired.

In order to support the outer end of the motor shaft 25 a bracket 29 is secured to the underneath side of the motor proper 26, and

extends forwardly and upwardly therefrom. A hearing is formed on the extreme outer end of the bracket 29, in which the outer end of the motor shaft 25 is journaled. The motor 26 is secured to a bracket 30 of a forked type, a second bracket 31 secured preferably to the underneath side of the operating table 11 having a tongue portion for engaging between the forks of the bracket 30. A pin 32 is journalled in the bearings thus formed by the tongue and forked portions of the respective brackets 30 and 31, thereby forming a pivotal mounting for the motor 26.

Although not shown, the connection between the driving means and the driven means may be modified to eliminate the transmitter shaft 21 together with the gear and pinion 22 and 20 respectively. I11 this construction, the grooved wheel 23 may be mounted directly on the auxiliary shaft 15 adjacent the pulley 14 whereafter the controlling means would operate to cause the motor 26 to pivot, whereby a frictional engagement may obtain between the grooved wheel and the wedged wheel in the manner just described.

A rocker arm 33 is tiltably mounted on a bracket 34 at a point between the ends thereof, which bracket 34 is secured to the underneath side of the operating table 11. One end of the rocker arm 33 is provided with a roller 35, rotatably mounted thereon for engaging an extension 36a of the bracket 30.

A lifter rod 37 is connected to the other end of the rocker arm 33 and extends downwardly therefrom to be secured to a complementary portion or lifting rod 38 as by means of clamp member 39. The clamping member 39 may be of any desired type, it being fixed to the lifter rod 38 and adjustably connected to the lifter rod 37 as by means of a set-screw.

The lower end of the lifter rod 38 is connected to the upper treadle rod 40 of the treadle 41, the latter being pivotally mounted between treadle supports 42. This latter described mechanism, including the lifter rods and the treadle member, are well known in the art and further description is therefore believed unnecessary.

In the operation of the power unit just described, when an operating pressure ap- 4 plied, as when treadle 41 is tilted in one direction the lifter rods 37 and 38 move downwardly to carry one end of the rocker arm 33 downwardly. The roller 35 engages and moves upwardly the extension 36a on which the motor 26 is mounted, thus tilting the lat ter and providing an operative relation or frictional engagement between the wedged, wheel 24 and the grooved wheel In this condition of the power unit rotation is imparted to the main shaft 12 of the sewing machine. \Vhen operating pressure is removed from the treadle 4-1, or when the controlling meansaretrippedmechanically,the weight of gravity causes the electric motor 26 to pivot downwardly on the'pin 32, carrying with it the one end of the rocker arm 33 having the roller 35 thereon, thereby raising the other end of the rocker arm 33 to bring the treadle 41 into its initial inoperative position.

As the rocker arm is tilted into its initial position by means of the weight of gravity, causing the motor 26 to drop downwardly, a brake 43 fixedly securedto the rocker arm is caused to engage an outer face of the grooved wheel 23. The brake 43 may be adjustable with respect to the rocker arm 33, and besides effecting an almost immediate stopping of the rotation of the main shaft 12, supports the motor 26 in its lower position and prevents a further downward displacement thereof. 3

Referring now to Figures 3 and 4 of the drawings, a second embodiment of this invention is shown therein, comprising the usual sewing machine or other intermittently operated device 44, having a main shaft driven by means ofa pulley connected between the shaft and a link. chain or belt 45 on wheel 46. A grooved wheel 47 is mounted on a shaft 48 which latter supports the pulley 46, and is in turn ournalled in suitable bearings 49 secured to'the underneath side of the operating table 50. An electric motor 51 is fixedly attached to the underneath side of the operating table 50, and has a balanced grooved wheel 52 mounted on the motor shaft 53 thereof, the recesses of the grooved wheels 47 and 52 occupying a substantially vertical plane.

A wedged wheel 53 rotatably mounted in forked ends of an adjustable arm 54, is adapted to engage in an operative position the wedged faces of the recesses of thewheels 47 and 52. The arm 54ispivotally mounted at one end thereof to a bracket 55 secured to the underneath side of the operating table 50. The wedged wheel 53 mounted on the free end of the arm 54 is adapted to engage the wedged surfaces of the wheels 47 and 52 simultaneously, and provide a frictional engagement therebetween when in an operative position. v

A rocker arm 56 is tiltably mounted ;be-- tween its ends on a bracket 57, which latter is fixedly mounted on the underneath side of the operating table 50. One end of the rocker arm 56 is provided with an engagingwheel 58 for engaging a flattened. portion of the underneath side of the arm 54. A lifter rod 59 is secured to the other end of the rocker arm 56 and extends downwardly therefrom,

to be adjustably connected to a complementary lifter rod member 60, the clamping member 61 providing for the adjustable engagement therebetween. The lower end of the lifter rod 60 is secured to the upper treadle rod 62 of a treadle 63 as in the manner described in the previous embodiment.

When an operating pressure is applied as by means of tilting the treadle 63, the lifter cause the wheel 58 to engage the arm 54,

thereby causing the chain of frictional wheels to become engaged, as previously described,

whereafter the main shaft of the machine is operated." When the operating pressure is removed, or the controlling mechanism is automatically tripped, the weight of gravity causes the arm 54 to drop downwardly carrying with it the wheel 58.and that end of the rocker arm 56, which action operates the treadle into an initial inoperative position.

WVhile but two embodiments of this invention are herein shown and described, it is to be understood that various modifications thereof may be apparent to those skilled in the art without departing from the spirit and scope of this invention, and therefore the same is to be limited only by the scope of the appended claims and the teaching of the prior art.

We claim:

1. In a sewing machine provided with a frame mounted on the top of a supporting platform and having internally disposed driving mechanism therefor, the combination of a fixed motor mounted on the underneath side of said supporting platform, a power transmitting pulley on said. motor shaft, a power receiving pulley on said driving mechanism, and pivotal means between said power transmitting and said power receiving pulleys for frictionally connecting the same whereby no moving part is exposed to the work on said supporting platform.

*2. In a sewing machine provided with a frame mounted on the top of a supporting platform. and having internally disposed driving mechanism therefor, the combination of a fixed motor mounted on the underneath side of said supporting platform, a power transmitting pulley on said motor shaft, a

power receiving pulley on saiddriving mech anism, and a friction wheel movable into and out of engagement with said power transmitwheel on said motor shaft and on said driving mechanism, and a wedged wheel movable into and out of engagement with said groove wheels for frictionally connecting the same whereby no moving part is exposed to the work on said supporting platform.

4. In a sewing machine provided with a frame mounted on the top of a supporting platform and. having internally disposed driving mechanism therefor, the combination of a fixed motor mounted on the underneath side of said supporting platform, a grooved wheel on said motor shaft and on said driving mechanism, a pivotally mounted wedged wheel mo'vable into and out of engagement with said grooved wheels for frictionally con necting the same whereby no moving partis exposed to the work on said supporting platform, and a foot treadle connected to said pivoted wedged Wheel for the operation thereof.

In witness whereof, we have hereunto subscribed our names.

HARRY SOPKIN.

BENJAMIN H. GORMAN. 

